1. Field of the Invention
The present invention relates to a dual band transceiver architecture for wireless communication. A signal reception portion and a signal emission portion are used for processing the multi-mode dual band transmitting/receiving signal so as to accomplish the receiving and emitting of the signal.
2. Description of the Prior Art
In the recent decades, due to the ban lifting by military and the development of technology, the wireless communication gradually replaces the traditional wired telephone communication and the unidirectional wireless transmitting/receiving. Furthermore, the function for transmitting massages merely by voice cannot meet the user's requirements. In order to promote the transmission quality and the functional service of the wireless communication, different communication protocols are established and applied. For example, in the third generation of mobile communication protocol, the bandwidth cannot be effectively applied and arranged, and therefore, the 2.4 GHz (gigahertz) communication band is selected. Practically, in the international protocol, the industrial, scientific and medical band (ISM Band) not only comprises 2.4 GHz band, but also has 5 GHz band. Therefore, some communication businesses have applied their products in this common-used band due to the free charge, openness and applicability of the common-used communication band.
Because of the applicability of the ISM band, many communication protocols are provided with the ISM band. The ISM band has been used in the 2.4 GHz and 5 GHz bands, such as 802.11a and 802.11b communication protocols for wireless local access network (WLAN) and the band for the Bluetooth technology are applied. Conventionally, the design of the product applying this communication protocol is to use two sets of transmitting/receiving devices and multiple frequency synthesizers to separately receive signals form different bands. If single one synthesizer is used for performing the modulation for the signal, only one band signal is processed by this design.
Please refer to FIG. 1. FIG. 1 is a perspective diagram of a prior art frequency synthesizing circuit. The prior art circuit comprises an antenna 700 connected to a band-pass filter 701, and the band-pass filter 701 is connected to a switch 702. When the antenna 700 receives the signal, the switch 702 will be so switched that the band-pass filter 701 will be connected to the first balance/imbalance device 703. Then, a low noise amplifier 705 will output the signal to a wave-mixing device 706, and the wave-mixing device 706 will receive a signal outputted by the low noise amplifier 705, and will receive an oscillation signal outputted by a local oscillator 707. The obtained down-converted signal will be outputted to a 1.06 G orthogonal wave-mixing device 710 separately connected to a seventh orthogonal wave-mixing device 708 and an eighth orthogonal wave-mixing device 709. Because the seventh orthogonal wave-mixing device 708 and the eighth orthogonal wave-mixing device 709 will receive signal outputted by the wave-mixing device 706 and further receive a 1.06 G orthogonal signal separately. Therefore, the signal is wave-mixed with the orthogonal signal so as to output an orthogonal down-converted signal and accomplish the down-conversion modulation for the signal.
In the signal emission portion, the orthogonal emitting the base frequency signal is separately inputted into the ninth orthogonal wave-mixing device 721 and the tenth orthogonal wave-mixing device 722 in the 5.3 G orthogonal wave-mixing device 720. Because the ninth orthogonal wave-mixing device 721 and the tenth orthogonal wave-mixing device 722 will separately receive a 5.3 GHz orthogonal up-sampling inputted from outside. Then, the signals are separately outputted to a subtractor 723 so as to connected to a power amplifier 724 via the subtractor 723. After the power amplifying for the signal is performed, the signal is then transmitted to another balance/imbalance device 704 for impedance matching. And the switch 702 will emit the signal by using the band-pass filter 701 and the antenna 700.
As described above, the prior art applies a single frequency synthesizer and the advantage of the circuit design so as to achieve the object of high integrality and simplifying the difficulty of design. However, the prior art technology merely solves the problems for the 5 GHz band, and cannot integrally modulate the multi-mode and multi-band signals.